Fan



Dec. 11, 1934. w A, GESE 1,983,606

FAN

Filed Feb. 12, 1931 Patented Dec. 11 1934 OFFICE Walter A. Geise, Flint,Micln, moi to Game I Motors Corporation, Detroit, Micln, a corporationof Delaware applicati n February 12, 1931, Serial No. 515,167 '1 1 onm'(01. 170-159) This invention relates to multi-blade fans of the screw orpropeller type, such as those which are used to draw cooling air throughthe radiator of an automotivevehicle and force it over the 5 propellingengine thereof.

' It has been found that the cooling fan of an automotive vehicle is thecause of a large part of the noise which is commonly attributed to thepropelling engine of the vehicle and, further- .more, that the noisecaused by the fan cannot be eliminated by redesigning the blades or byany other expedient known or practised prior to the time of myinvention. During the course of." experiments, which were conducted withthe object of producing a fan which would operate more noiselessly thanthe fans then known, I discovered that a'much quieter fan was producedwhen theblades were so arranged that the angle betweenone blade and thenext was greater or less than that between the last-mentioned blade andthe following blade.

My invention may be embodied in multi-blade fans which have even oruneven numbers of blades; and in either type of fan, the angle betweenone blade and the following blade may be different than the anglebetween every other pair of adjacent blades or the angle between oneblade'and the following blade may be different than the angle betweenanother pair orother pairs of adjacent blades but equal to the anglebetween still another-pair or other pairs of adj acent blades. In thecase of multi-blade fans which have even numbers of blades, in number atleast four, the blades may be arranged in a special manner which hasobvious advantages, viz. that in whichthe center lines of pairs of theblades are aligned. In this construction, the angle between one bladeand the following blade will differ from the angle between'thelast-mentioned blade and the next blade, but'theangles between thediametrically opposite pairs of blades of necessity, be equal.

For a better understanding of the nature and objects of my invention,reference is made to the following specification in which. are describedthe preferred embodiments of my invention which are illustrated in ,theaccompanying drawing, in which:

Figure l is a fragmentary side elevation of the front end of anautomotive vehicle on which is installed a. cooling fan in which isembodied my invention.

Figure 2 is a front elevation of the cooling which is shown in Figure 1.i

Figure 3 is a front elevation of a modified form of cooling fan.

fan

' In the drawing, referring mommy to Figures 1 and 2, the referencecharacter 9 indicates the water cooling radiator of an automotivevehicle and the reference character 10 the propelling engine thereof. Todraw .cooling 'air through the radiator and force it over the engine,

there is' provided a cooling fan 11 which is arure 2, the center linesof the blades 13 and 14 are aligned, respectively, with the center linesof the bladeslfi and 15, and, consequently, the angle between the centerlines of the blades 13 and 141s equal to the angle between the centerlines of the blades 15 and 16 and the anglevbetween the center lines ofthe blades Band 15 is I equal tothe angle between the center lines ofthe blades 14 and 16. But, as will'also be apparent from a glance atFigure 2, the angle between the center lines of the blades 13 and 15 andthe blades 14 and 16 is considerably-greater than the angle between thecenter hues of the blades 13 and '14 and. the blades 15 and 16. Thevalue of the difference between these angles which will give the mosthighly satisfactory results will depend upon the characteristics of thevehicle in which the fan is installed and may, be determinedexperimentally. In the fan which is shown in Figures 1 and 2 the anglebetween the center lines of the blades 13 and 14 and the blades 16 and15 is 76 degrees, while that between the center lines of the blades 15and 13 and the blades 14 and 16 is 104 degrees. A fan in which theblades are arranged as described in the preceding sentence has beenfound to be the. most satisfactory for use on the series 8-50 models ofthe present Buick automobiles.

In Figure 3 of the drawing, there is shown a fan which consists of a hub(not shown) to which there are secured and on which there are mountedfive propeller or screw type fan blades 17, 18, 19, and 21. It will beapparent from an inspection of Figure 3 that the angle between thecenter line of each blade and the center line of the following bladedifiers from that hetween the center lines of every other pair of ad-.lacent blades.

When a fan in which is embodied my invention is operated, 'much lessnoise results than when a fan of equal capacity in which all blades twotypes of fans and apparently results Ironr the fact that blades of myfans set up in the current of air generated by the fan vibrations.

of different frequencies which interfere with and tend to attenuate eachother and thus reduce the total volume of noise created by the operationof the fan. To eliminate unbalance in my fans, when it exists, some orthe blades may be made heavier, orlarger and heavier than, others orcounterweights may be applied to the fan assembly.

Although I have shown and described as preferred embodiments of myinvention, four-blade and five-blade fans, it will be understood thatthe principles underlying my invention may be incorporated in fans whichhave a greater number of blades as well as in two-blade and threebladefans.

In the claim, the word blade" is used to designate a main blade asdistinguished from an auxiliary vane 01 a compound blade.

vI claim:

In an automotive vehicle, the combination of a radiator, an internalcombustion engine, and a rotary fan which is located between theradiator and the engineand operated by the engine to draw air throughthe radiator and circulate it over the engine and which consists of aplurality oi substantially coplanarly disposed blades arranged aroundthe axis of rotation so that the angle which separates one blade fromthe following blade so difiers from that which separates thelast-mentioned blade from the following blade that the sound waves setup by the blades have such characteristics that the noise createddurlngthe operation of the fan is audible to a minimum degree.

WALTER A. GEISE.

